A new material is formed in <span>result of a chemical change. Typically, the chemical changes always make the new material.</span><span />
The atomic mass would be 28.08535 amu. Multiply 27.9769 by .92297 = 25.803. Multiply 28.9765 by .046832 to get 1.357. Multiply 29.9738 by .03872 to get .925351136. Add 25.803 + 1.357 + .03872 to get 28.08535 amu
A compound is where two or more elements have chemically bonded, and a mixture is where there are two or more elements are grouped together, but they are not chemically bonded.
An example of a mixture would be salt dissolved in water, and an example of a compound would be water (which is made up of 2 Hydrogen and 1 Oxygen bonded together)
tl;dr: I would go with B, basically.
